Animal models are essential in the development of preventive, diagnostic and therapeutic procedures for diseases in a wide spectrum of fields including neural stem cell (NSC) research. To elicit or identify the potency of stem cells in animal models is a critical procedure in the development of further applications. Chicken and mammalian brains share similar activities and mechanisms of migration pattern and differentiation during development (Alvarez-Buylla and Nottebohm, 1988; Aroca et al. 2006).
NSCs have been demonstrated to reside in the sub ventricular zone (SVZ) of the lateral ventricle and the dentate gyrus subgranular zone (SGZ) of the hippocampus in rodent (Lim et al. 2007). Neural stem cells (NSCs) are self-renewing and generating neuronal and glial cells in nervous system. Therefore, transplantation of neural stem cells (NSCs) has been proposed as therapy for a wide range of central nervous system disorders, including neurodegenerative diseases (e.g., Parkinson's disease), demyelinating disorders (e.g., multiple sclerosis), stroke, and trauma. Although there is great hope for the success of such therapies, the clinical development of NSC-based therapies is still in its infancy.
To establish the optimal cell preparation procedures, assays are needed to evaluate the potency of NSCs, i.e., their ability to perform stem cell functions after injection into a patient, thereby effecting tissue repair. Ideally, it would be desirable to have a system that would allow assessing the stem cells' potency in a reliable way for every stem cell manufacturing protocol.
To understand the potency of NSCs and stimulated NSCs is the greatest challenge in the development of replacement therapies. Although significant advances in this field have been made over the past decade, no cost effective and accessible assay is currently available. Expression marker profiles have been used with some success to identify stem cells capable of assuming a neural phenotype. However, these profiles do not often provide a good indication of stem cell potency in an in vivo environment.
Embryonic mouse models have been used in some capacity for measuring the potency of NSC in vivo (Proc Natl Acad Sci USA. Dec. 20, 2005; 102(51): 18644-8). However, these models are expensive to maintain and their isolation in utero and small size makes them difficult to work with. The gestation period for mice also places a time constraint on this model. What is needed in the art therefore is a quick, inexpensive and easily accessible in vivo model for the measurement of NSC potency.